Pseudoexfoliation of the lens capsule and liberation of iris pigment

Proteomic characteristics of the aqueous humor in Uyghur patients with pseudoexfoliation syndrome and pseudoexfoliative glaucoma

Pseudoexfoliation syndrome (PEX) is characterized by the deposition of fibrous pseudoexfoliation material (PEXM) in the eye, and secondary glaucoma associated with this syndrome has a faster and more severe clinical course. The incidence of PEX and pseudoexfoliative glaucoma (PEXG) exhibits ethnic clustering; however, few proteomic studies related to PEX and PEXG have been conducted in Asian populations. Therefore, we aimed to conduct proteomic analysis on the aqueous humor (AH) obtained from Uyghur patients with cataracts, those with PEX and cataracts, and those with PEXG and cataracts to better understand the molecular mechanisms of the disease and identify its potential biomarkers. To this end, AH was collected from patients with cataracts (n = 10, control group), PEX with cataracts (n = 10, PEX group), and PEXG with cataracts (n = 10, PEXG group) during phacoemulsification. Label-free quantitative proteomic techniques combined with bioinformatics were used to identify and analyze differentially expressed proteins (DEPs) in the AH of PEX and PEXG groups. Then, independent AH samples (n = 12, each group) were collected to validate DEPs by enzyme-linked immunosorbent assay (ELISA). The PEX group exhibited 25 DEPs, while the PEXG group showed 44 DEPs, both compared to the control group. Subsequently, we found three newly identified proteins in both PEX and PEXG groups, wherein FRAS1-related extracellular matrix protein 2 (FREM2) and osteoclast-associated receptor (OSCAR) exhibited downregulation, whereas coagulation Factor IX (F9) displayed upregulation. Bioinformatics analysis suggested that extracellular matrix interactions, abnormal blood-derived proteins, and lysosomes were mainly involved in the process of PEX and PEXG, and the PPI network further revealed F9 may serve as a potential biomarker for both PEX and PEXG. In conclusion, this study provides new information for understanding the proteomics of AH in PEX and PEXG.

Secondary glaucoma: Toward interventions based on molecular underpinnings

Glaucoma is a heterogeneous group of progressive diseases that leads to irreversible blindness. Secondary glaucoma refers to glaucoma caused by a known underlying condition. Pseudoexfoliation and pigment dispersion syndromes are common causes of secondary glaucoma. Their respective deposits may obstruct the trabecular meshwork, leading to aqueous humor outflow resistance, ocular hypertension, and optic neuropathy. There are no disease-specific interventions available for either. Pseudoexfoliation syndrome is characterized by fibrillar deposits (pseudoexfoliative material) on anterior segment structures. Over a decade of multiomics analyses taken together with the current knowledge on pseudoexfoliative glaucoma warrant a re-think of mechanistic possibilities. We propose that the presence of nucleation centers (e.g., vitamin D binding protein), crosslinking enzymes (e.g., transglutaminase 2), aberrant extracellular matrix, flawed endocytosis, and abnormal aqueous-blood barrier contribute to the formation of proteolytically resistant pseudoexfoliative material. Pigment dispersion syndrome is characterized by abnormal iridolenticular contact that disrupts iris pigment epithelium and liberates melanin granules. Iris melanogenesis is aberrant in this condition. Cytotoxic melanogenesis intermediates leak out of melanosomes and cause iris melanocyte and pigment epithelium cell death. Targeting melanogenesis can likely decrease the risk of pigmentary glaucoma. Skin and melanoma research provides insights into potential therapeutics. We propose that specific prostanoid agonists and fenofibrates may reduce melanogenesis by inhibiting cholesterol internalization and de novo synthesis. Additionally, melatonin is a potent melanogenesis suppressor, antioxidant, and hypotensive agent, rendering it a valuable agent for pigmentary glaucoma. In pseudoexfoliative glaucoma, where environmental insults drive pseudoexfoliative material formation, melatonin's antioxidant and hypotensive properties may offer adjunct therapeutic benefits. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

The depigmentation degree of iris pigment epithelium in pseudoexfoliation syndrome

BACKGROUND

To compare the optical density of iris pigment epithelium (OD_IPE) and iris stromal thickness (IST) measurements in patients having pseudoexfoliation syndrome (PXS) and age-gender matched participants.

METHODS

This is a cross-sectional study. Patients with PXS were enrolled in the study group. Age and gender-matched healthy subjects with no evidence of PXS were recruited as controls. After a comprehensive ophthalmological evaluation, the anterior segment images were acquired using anterior segment spectral-domain optical coherence tomography (AS SD-OCT). The acquired pictures were further analyzed using the ImageJ program. Two investigators measured the OD_IPE and the IST of the subjects, and the repeatability and reproducibility were checked. SPSS program was used for statistical analysis.

RESULTS

The PXS group was comprised of twenty-two eyes (n = 22 patients), and the control group contained twenty-six eyes of 26 age and gender-matched healthy subjects. The mean temporal OD_IPE of the study group was found to be decreased significantly in comparison to the mean temporal OD_IPE of the control eye (p = 0.018). Both the mean nasal (N) and temporal (T) ISTs of the PEX eyes were thinner than the control eyes (p = 0.006 and p = 0.002, respectively). The mean baseline IOP was found to significantly negatively correlate with the OD_IPE in the PEX group at both N and T sides (r = -0.531, p = 0.011 and r = -0.685, p < 0.001, respectively).

CONCLUSION

The pupillary margin IPE was found more depigmented, and the mean N and T IST were significantly thinner in the PEX group by comparison with the age-gender matched healthy controls. The mean baseline IOP was negatively correlated with the pupillary margin's IPE pigmentation degree in patients with PXS.

Epidemiology of Exfoliation Syndrome

BACKGROUND

From a historical standpoint the epidemiology of exfoliation syndrome (XFS) is one of the most controversial subjects in ophthalmic literature. Current literature abounds with studies on the prevalence of XFS in various ethnic populations and clearly XFS is a common condition, but its true prevalence is difficult to ascertain. Overall, XFS is considered to be the most common identifiable cause of glaucoma worldwide.

PURPOSE

This review critically examines the published literature documenting the epidemiological features of XFS and attempts to provide a unified concept concerning existing controversy.

METHODS

A critical review of selected literature pertaining to the epidemiology of XFS.

RESULTS

It is well established that XFS and the ensuing exfoliative glaucoma have a worldwide prevalence and a progressively increasing age-related incidence. The prevalence of the condition is significantly underestimated. Many past studies have proposed clear geographic variations within and between ethnic groups. In contrast, there has also been some epidemiological evidence suggesting that the prevalence of XFS is similar within various ethnic groups. Published literature fails to address the potential role and impact of suspected exfoliation cases in the reported prevalence figures of the condition. Incidence figures for the condition are limited and vary extensively. Cumulative data have indicated that several, as yet partly understood genetic, ethnic, and environmental factors contribute to the varied prevalence of this condition.

CONCLUSIONS

Further understanding on XFS epidemiology is needed. Only a future large prospective study conducted by the same investigators, using similar methodologies for different ethnic populations will prove beyond doubt the hypothesis that significant geographic variations exist. Since patients with exfoliative glaucoma are at significant risk of losing vision it is vital to elucidate the causes and the risk of developing XFS. To reach this goal, it is important to better delineate the early changes of XFS and to focus research efforts on modifiable factors for XFS development.

Conjunctival changes in different clinical variants of early pseudoexfoliation

PURPOSE

To evaluate the conjunctival signs in different forms of pseudoexfoliation (PXF) syndrome to identify signs predicting early forms of the disease.

METHODS

This observational study included patients with newly diagnosed PXF screened in the outpatient department of glaucoma services. Slit lamp photographs were captured in low and high magnification after full dilatation, and details like melanotic pigmentation, vascularity and tortuosity of vessels, scarring if any, presence of pterygium and actinic changes along with basal Schirmer's test were analysed. Variables in each subtype of PXF previously described by us, namely radial pigmentary (group A), combined pigmentary and classical (group B) and classical PXF (group C), were analysed and compared to age-matched controls. The differences between manifest (group B + C) and unmanifest or early form (group A) were also compared.

RESULTS

A total of 89 eyes from 55 patients (M/F = 38:17, 21 unilateral, 34 bilateral, 48 group A, 10 group B and 31 group C) were compared with 40 controls. The Schirmer's test was statically lower in patients with manifest PXF (10 ± 1.4 mm) and unmanifest PXF (14 ± 0.6 mm), p < 0.001. The most frequent conjunctival finding (n = 88) in this cohort was lightly pigmented melanotic pigmentation present close to limbus without evidence of any feeder vessels or actinic changes and associated with pupillary ruff atrophy in the same quadrant. Analysing different PXF forms, there was conjunctival melanosis in one or all quadrants in all forms of PXF which was more prominent in manifest PXF, present in a mean 2 ± 1.7 quadrants in unmanifest and manifest PXF, p = 0.01.

CONCLUSION

Conjunctival melanosis with associated pupillary ruff atrophy in the same quadrant may be the earliest signs of early pseudoexfoliation.

Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma: A Review of the Literature with Updates on Surgical Management

Pseudoexfoliation syndrome (PES) is a systemic disorder caused by progressive accumulation of extracellular material over various tissues. PES usually determines increased intraocular pressure, changes in the anatomical aspects of the optic nerve, and visual field alterations leading to the diagnosis of pseudoexfoliation glaucoma (PEG). Use of topical medical treatment usually leads to poor results in terms of long-term follow-up but many surgical techniques, such as Argon Laser or Selective Laser Trabeculoplasty, have been proposed for the management of PEG affected patients. The present paper is a review on the pseudoexfoliation syndrome and pseudoexfoliation glaucoma with an update on surgical management.

Geographic and climatic factors associated with exfoliation syndrome

OBJECTIVE

To identify geographic and climatic risk factors associated with exfoliation syndrome (ES).

METHODS

A retrospective study of 626 901 eye care recipients, dating from 2001 to 2007 from 47 US states in a managed care network. Incident ES cases-patients (N = 3367) were identified by using billing codes. We assessed the risk of ES by geographic latitude tier in the continental United States and assigned state-level climatic data (eg, ambient temperature, elevation, and sun exposure) according to patients' residential location. The hazard of ES was calculated by using multivariable-adjusted Cox proportional hazards regression models.

RESULTS

Compared with middle-tier residence, northern-tier residence (above 42°N) was associated with an increased hazard of ES (adjusted hazard ratio [HR], 2.14; 95% confidence interval [CI], 1.94-2.35). Southern-tier (below 37°N) was associated with a reduced hazard of ES (HR, 0.83; 95% CI, 0.75-0.93). Excluding whites did not change these associations. After adjustment for joint environmental effects, for every 1° increase in July high temperature, the hazard of ES decreased by 9% (HR, 0.91; 95% CI, 0.89-0.93); for every 1° increase in January low temperature, the hazard decreased 3% (0.97; 0.96-0.98). For each additional sunny day annually, the hazard increased by 1.5% (HR, 1.02; 95% CI, 1.01-1.02) in locations with average levels of other climatic factors.

CONCLUSION

Ambient temperature and sun exposure may be important environmental triggers of ES.

Prevalence of exfoliation syndrome in Finland

Three separate investigations are reported, covering a total of 795 patients from different parts of Finland, two of them consisting of inmates of old people's homes in two towns (N = 205 and 262) and one a randomly selected population from a rural commune (N = 328). They show the mean prevalence of exfoliation syndrome (PS) to be 14.2% in age group 60 less than or equal to 69 years, 21.9% in age group 70-79 and 34.7% in age group greater than or equal to 80. The prevalence increases statistically significantly with age. The mean prevalence of PS in all three groups was 22.4%. No isolate-like accumulation of PS could be demonstrated. The figures seem representative of the hole country.

Exfoliation syndrome in various ethnic populations

This introductory lecture to the epidemiological session in the Workshop on the Exfoliation Syndrome (ES) gathers together figures for the prevalence of ES around the world. Prevalence figures from published reports are shown in the text separately for each country. Four ways of comparing the prevalences are used. 1) Prevalences in people over 60 years of age, 2) Percentages of glaucoma in persons with ES, 3) Percentages of ES in patients with glaucoma or ocular hypertension, with separate statistics for the proportion of capsular glaucoma in patients treated with laser trabeculoplasty (LTP), 4) Prevalence of ES in patients with cataract. The major differences in prevalence can partly be explained by the different techniques used in the investigations. Very few authors have studied people in different countries, which is the best way of obtaining comparable results. The author has personally studied Finns, Lapps, Eskimos in Greenland, Canada and Alaska, Icelanders, populations in Tunis, India and Peru and four populations in the USSR by the same technique. The prevalences vary from 0% in Eskimos to 21% in Finns over 60 years of age, and are at the same high level in Lapps, Finns, Russians in Novosibirsk and Icelanders, but significantly lower in all the others. The results support the opinion that ES is not uniformly distributed in all countries, and this is confirmed by many reports from different countries in this workshop.

Exfoliation syndrome prevalence in the glaucoma population of South Louisiana

A prospective study was performed to determine the prevalence of exfoliation syndrome in a glaucoma population of South Louisiana. Five hundred consecutive open angle glaucoma patients over 50 years of age (median age 70.6 years) from both indigent clinic and private referral sources were examined for the presence of exfoliation material on the lens capsule. The prevalence in caucasian patients was 2.7%, blacks 0.4%, combined 1.4%. This compares with a reported prevalence of exfoliation syndrome among patients with open angle glaucoma in the United States of 3% to 28%, Denmark of 26%, Ireland of 66%, and Sweden of 75%. This low prevalence may be a reflection of the ethnic origin of the population, but other explanations are considered.

Light microscopy of the exfoliation syndrome

The exfoliation syndrome affects all structures of the ocular anterior segment, as well as the conjunctiva and occasionally, nonocular structures. The exfoliative material has been shown by a series of light microscopic and gross anatomic studies to be only loosely adherent to the anterior lens capsule, zonules and anterior vitreous face, and firmly adherent to the equatorial lens capsule and posterior epithelium of the iris and the nonpigmented ciliary epithelium. Electron microscopy demonstrates that, in these latter regions, exfoliation material consisting of characteristic, cross-banded fibrils embedded in an amorphous matrix, is present both within the epithelial cells and associated with a disorganized, reduplicated basement membrane. These findings suggest that the material arises from the epithelium of the lens, iris and ciliary body, possibly the result of an underlying metabolic disorder. From these areas, the material enters the aqueous humor and later deposits on the anterior lens capsule, zonules, vitreous face, anterior surface of the iris, and trabecular meshwork. Histochemical studies demonstrate the presence of glycosaminoglycans, which may comprise the interfibrillar portion of the exfoliative material. Other studies demonstrate histochemical similarities between exfoliative material and zonules and are supported by recent work suggesting that the exfoliative fibrils are related to the microfibrillar portion of elastin. Although some reports suggest similarities between exfoliative material and amyloid, a majority of histochemical studies do not support this possibility.

Exfoliation syndrome in the southeastern United States. I. Prevalence in open-angle glaucoma and non-glaucoma populations

A prospective study of 2,121 patients, 30 years of age or older, examined in two clinics in the southeastern United States with dilated slit-lamp biomicroscopy, revealed the exfoliation syndrome in 1.6% of the total population and in 6.0% of an open-angle glaucoma subpopulation. All but one of the 33 patients with exfoliation syndrome were over age 60 years, and the prevalence of exfoliation syndrome in the subgroup over age 60 was 3.2%. Among the patients over age 60 who did not have open-angle glaucoma, 1.6% had exfoliation syndrome. By chi square analysis, the prevalence of the exfoliation syndrome in the over age 60 population without glaucoma was found to be significantly less (P = 0.00009) than reported in studies from other geographic areas.

Matrix metalloproteinases and their inhibitors in the chamber angle of normal eyes and patients with primary open-angle glaucoma and exfoliation glaucoma

BACKGROUND

In glaucoma, extensive pathological changes occur in the trabecular meshwork (TM) and juxtacanalicular tissue of the chamber angle. Aqueous humor drainage is disturbed due to the accumulation of extracellular matrix (ECM) material in the outflow system. Matrix metalloproteinases (MMPs) remodel ECM material and, thus, they may have a role in regulating outflow facility and intraocular pressure (IOP). This study examined the expression of MMPs and tissue inhibitors of MMPs (TIMPs) in the chamber angle of normal eyes and in primary open-angle glaucoma (POAG) and in exfoliation glaucoma (ExG).

METHODS

TM tissues were isolated from healthy donor eyes for corneal transplantation. Specimens of the inner wall of Schlemm's canal and the juxtacanalicular tissue were collected from patients with POAG or ExG during deep sclerectomy operation. Monoclonal antibodies against MMPs (MMP-1, -2, -3, and -9) and antibodies against TIMPs (TIMP-1, -2, and -3) were used for immunohistochemical staining.

RESULTS

Immunoreactivity for MMP-2, TIMP-2, or TIMP-3 was observed in human normal TM and in the inner wall of Schlemm's canal. In general, immunoreactions for all of the tested MMPs were more intense in POAG samples than in ExG samples or in the control group. The only exception was the MMP-2 level, which was the highest in the control group. The staining intensity of MMP-1 or MMP-3 was significantly higher in POAG when compared to ExG. TIMP-1 was significantly increased in POAG compared with ExG and there were no marked differences in the levels of TIMP-2 or TIMP-3 between POAG and ExG. The ratios of MMP-1/TIMP-1 and MMP(1+2+3+9) and TIMP(1+2+3) were significantly higher in samples from POAG compared to those of ExG.

CONCLUSIONS

Our results reveal an expression imbalance between MMPs and their endogenous tissue inhibitors in tissue samples from patients with POAG and ExG. Differences in immunohistochemical reactions reflect discrete local pathogenic mechanisms involved in POAG and ExG. With respect to the proposed role of MMPs in the remodeling of ECM material, this may point to a weaker reactivity to the accumulation of ECM material in TM in ExG than POAG eyes.

Characterizing pseudoexfoliation syndrome through the use of ultrasound biomicroscopy

PURPOSE

To determine the clinical utility of ultrasound biomicroscopy (UBM) in diagnosis of pseudoexfoliation (PEX) syndrome by characterizing the lens capsule and zonules before cataract surgery.

SETTING

Veterans Administration Hospital, East Orange, and University of Medicine & Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey, USA.

METHODS

Ultrasound biomicroscopy was performed on 10 patients clinically diagnosed with PEX syndrome. The clinical diagnosis was made by the presence of fibrillin deposits on the anterior lens capsule, lack of pigment at the pupillary ruff, and poor pharmacologic dilation. Five persons without PEX were used as controls. The thickness of the anterior lens capsule was measured in 5 locations in each eye: centrally and in the peripheral lens capsule superiorly, inferiorly, nasally, and temporally. Four measurements were taken from the zonule at the thickest point on each fiber. The UBM also found the presence or absence of nodular deposits on the zonules.

RESULTS

The anterior and peripheral lens capsule in patients with PEX was thicker than that in the control group. Additionally, patients with PEX had thicker zonules than the control group and had nodular deposits present; the control group had no deposits. These differences were all significant with a 99% confidence interval.

CONCLUSIONS

A thicker anterior lens capsule and lens zonule nodules were associated with PEX. These abnormalities can be visualized with the UBM to confirm the diagnosis of PEX and identify patients at risk for operative complications.

Exfoliation syndrome: clinical and genetic features

We have ascertained a large number of individuals and families with exfoliation syndrome in order to clarify the disorder's mode of inheritance. Patients with exfoliation syndrome and their relatives were recruited from the practices of a group of ophthalmologists in Maritime Canada. The degree to which the subjects were affected was graded according to a standardized 1-4-point clinical scheme. Pedigrees were constructed from information supplied by family members and from genealogical sources. A total of 782 patients and relatives participated, of whom 467 were definitely affected. The mean age of affected males and females did not differ significantly, but females appeared to be more severely affected at ascertainment than males. More than half of the affected subjects had definite exfoliation in only one eye. Approximately 30 multiplex families were discovered, including one containing 23 affected members among a total of 137 examined individuals that constitutes the largest exfoliative pedigree thus far described. We observed well-documented paternal transmission of the trait, a finding that has not to our knowledge been previously reported. Clustering of cases in the families provides evidence for the involvement of genetic factors. The possibility of homozygosity is suggested in a few patients by the earlier or more frequent presentation of the disorder in the offspring of two affected parents or consanguineous pairings. Although a multifactorial mode of inheritance cannot be excluded, exfoliation syndrome appears to be inherited as an autosomal dominant trait whose late onset and incomplete penetrance poses a significant but not insuperable obstacle to pedigree construction.

Exfoliation syndrome

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.

Exfoliation syndrome and exfoliation glaucoma

Exfoliation syndrome abnormal deposition in the anterior segment of the eye of an unknown substance thought to be related to elastic fibres and basement membrane components is associated with accelerated cataract progression. increased frequency of intraoperative and postoperative complications and increased risk for glaucoma and. therefore, is a clinically important finding. A clear association has been shown with age. The syndrome occurs worldwide but its prevalence seems to vary from country to country. The best-known sign of exfoliation syndrome is deposits of greyish-white material on the anterior lens surface. Sometimes exfoliation material can also be seen at the pupillary border, on the anterior iris surface, corneal endothelium, and on the anterior vitreous face. When clinically detected, exfoliation syndrome is somewhat more often unilateral than bilateral. According to recent investigations clinically unilateral exfoliation syndrome is probably never truly unilateral but rather asymmetric, because exfoliation material has been detected ultrastructurally and immunohistochemically around iris blood vessels of the nonexfoliative fellow eyes. Indeed, electron microscopy identifies in various organs of patients with exfoliation syndrome fibrils similar to those seen in intraocular exfoliation deposits. Other clinical signs associated with exfoliation syndrome are pigment dispersion, transillumination defects of the iris and reduced response to mydriatics. In unilateral exfoliation syndrome, intraocular pressure (IOP) of the exfoliative eye is approximately 2 mmHg higher than IOP of the nonexfoliative fellow eye. Whether elevated IOP, vascular changes or exfoliation syndrome itself is the main factor causing optic nerve head damage and conversion of an exfoliative eye to glaucomatous, is not known. Glaucoma in the exfoliation syndrome has been shown to have a more serious clinical course than in primary open-angle glaucoma (POAG). At the time of diagnosis, IOP and its diurnal variation are generally higher and visual field defects tend to be greater in exfoliation glaucoma than in POAG. Because the decrease in lOP variation and lowering of the mean IOP level has been shown to improve visual field prognosis more in exfoliation glaucoma than in POAG, the glaucomatous process is considered to be more pressure-related in exfoliation glaucoma. Furthermore, progression of optic disc damage has been shown to be similar in exfoliation glaucoma and POAG when lOPs are lowered to a comparable level by the treatment. However, vascular disturbances in the posterior segment of the eye might after all be of equal importance in these two types of glaucoma; optic disc haemorrhages and venous occlusions have been reported to be as frequent in exfoliation glaucoma as in POAG. Perhaps in exfoliation glaucoma circullatory disturbances combined with high IOP lead to a particularly relentlessly progressing form of the disease.

Bimanual trabecular aspiration in pseudoexfoliation glaucoma: an alternative in nonfiltering glaucoma surgery

OBJECTIVE

The primary cause of intraocular pressure (IOP) elevation in pseudoexfoliation glaucoma is obstruction of the intertrabecular spaces by exfoliation material. Previously, the authors reported on a new concept of nonfiltering glaucoma surgery-trabecular aspiration-designed to increase trabecular outflow in pseudoexfoliation glaucoma. In the current study, a description of the modified instrument, its refined surgical technique, and long-term clinical results will be given to substantiate the efficacy of trabecular aspiration in the surgical management of pseudoexfoliation glaucoma.

STUDY DESIGN

The study design was a prospective and nonrandomized study.

PARTICIPANTS

A total of 68 eyes of 54 patients suffering from medically uncontrolled pseudoexfoliation glaucoma were treated by bimanual trabecular aspiration. Thirty-four eyes of 28 pseudoexfoliative patients treated by standard trabeculectomy constituted the control group.

INTERVENTION

Trabecular debris and pigment were cleared with a suction force of 100 to 200 mmHg under light tissue-instrument contact using a modified intraocular aspiration probe. The aspiration cannula is 400 microm in diameter and horizontally angulated at 45 degrees. Irrigation of the anterior chamber was performed via a separate irrigation cannula.

MAIN OUTCOME MEASURES

The IOP and number of medications before and after surgery were measured.

RESULTS

In 42 eyes of 36 patients, trabecular aspiration was performed in combination with cataract extraction and lens implantation. The IOP dropped from 32.4 +/- 7.2 mmHg (range, 23-52 mmHg) under maximal tolerated medical therapy before surgery to 18.7 +/- 1.7 mmHg (range, 16-23 mmHg) at 2 years after surgery, with 54% of patients being controlled without medication. In 22 eyes of 19 patients, trabecular aspiration was performed as primary surgical intervention. The IOP dropped from 31.3 +/- 7.1 mmHg (range, 23-42 mmHg) before surgery to 16.8 +/- 3.4 mmHg (range, 12-23 mmHg) at 18 months after surgery, with 45% of patients not taking medication.

CONCLUSIONS

Bimanual trabecular aspiration is safe and efficacious in decreasing IOP both with and without cataract extraction in pseudoexfoliation glaucoma. However, there seems to be a slight regression in effect over time attributed to undisturbed liberation of exfoliative debris. Argon-laser trabeculoplasty before trabecular aspiration reduces the IOP-lowering effect of this procedure. A prospective, randomized, multicenter study is warranted to finally assess the potential of trabecular aspiration in pseudoexfoliation glaucoma.

Pseudoexfoliation syndrome and secondary cataract

AIM/BACKGROUND

The pseudoexfoliation (PEX) syndrome is frequently associated with impairment of the blood-aqueous barrier. This study analysed if this might stimulate secondary cataract following cataract extraction.

METHODS

This historical cohort study included 197 eyes of 197 patients (99 with and 98 without PEX) that underwent extracapsular cataract extraction with posterior chamber lens implantation (PMMA optic) between 1985 and 1991. Secondary cataract was defined as opacification of the axial posterior capsule and decrease of visual acuity by two or more lines. Mean follow up was 23.8 months. For statistical analysis, the Kaplan-Meier method and multivariate Cox regression analysis were used.

RESULTS

Secondary cataract was observed within 24 months in 35% (SD 7%) of all eyes, and was significantly more frequent in eyes with PEX (45 (11)%) than in eyes without PEX (24 (9)%, p < 0.03). Eyes with diabetes mellitus (n = 32) showed a significantly lower frequency of secondary cataract (11 (11)%) than eyes without diabetes mellitus (39 (8)%, p < 0.01). The influences of sex, open angle glaucoma, type of cataract, surgeon, positioning of IOL, and phacoemulsification versus nuclear expression on secondary cataract did not reach statistical significance.

CONCLUSION

The higher frequency of secondary cataract could be considered as another potential complication of cataract surgery in eyes with PEX.

A histopathologic study of iris changes in pseudoexfoliation syndrome

PURPOSE

To investigate the histopathologic causes for the most prominent clinical observations of the iris of patients with pseudoexfoliation syndrome (PXS), particularly poor mydriasis but also atrophy of the iris pigment epithelium with anterior chamber melanin dispersion, stromal atrophy, and vascular changes.

METHODS

Thirty-three iris specimens from patients with PXS with and without glaucoma were investigated by transmission electron microscopy with special regard to sphincter and dilator muscle tissues.

RESULTS

Pseudoexfoliation fibers were observed consistently in association with fibroblasts and melanocytes in the iris stroma, endothelial cells and pericytes of vessels, both anterior and posterior pigment epithelial cells, and muscle cells of sphincter and dilator muscles. The various cell types showed uniformly surface cell membrane excavations with PXS fibers, indicating local PXS production. Focal disintegration of the pigment epithelial layers was associated with unusual PXS material aggregations along the apical aspects of epithelial cells. Compared with age-matched control specimens, the muscle cells showed, in addition to PXS production, remarkable degenerative and atrophic changes in PXS eyes.

CONCLUSION

The authors suggest that abnormal extracellular matrix production and/or vascular abnormalities leading to tissue hypoxia cause degenerative tissue changes and that atrophy of muscle cells might potentiate the reduction of dilating properties of the iris.

Frequency of exfoliation syndrome in Greek cataract patients

The frequency of exfoliation syndrome (EXS) was investigated in a group of Greek patients undergoing extracapsular cataract surgery. Five hundred and nine (509) consecutive cataract patients without any other manifest ocular abnormality were prospectively examined for the presence of EXS. Patients were clinically divided into 3 groups: group I (EXS group) consisted of patients in whom exfoliation material deposition could be seen; Group II (possible EXS group) comprised patients who demonstrated a number of pigmentary signs and group III (normal subjects) comprised patients with senile cataract and no sign of EXS. EXS was found in 140 (28%) of our patients, possible EXS in 119 (23%) and the rest (49%) had no evidence of EXS. Patients with EXS were older (mean age 73.8) when compared to the possible EXS group (70 years) and the control group (64.7 years). The IOP was significantly higher in patients with EXS (mean 15.5 mmHg versus 14.3 mmHg in the other two groups). Blue irides were significantly more common in patients with EXS (19%) than in the possible EXS group (14%) and the controls (4%). EXS is common in Greek cataract patients and this study has identified a large group of patients who may be at an early stage of development of the condition. EXS may predispose to the development of cataract in Greek patients.

Color Doppler imaging of the ophthalmic artery blood flow spectra of patients who have had a transient ischemic attack. Correlations with generalized iris transluminance and pseudoexfoliation syndrome

PURPOSE

To study the interrelations among pseudoexfoliation syndrome (PXS), abnormal iris transluminance, and ophthalmic artery blood flow in a controlled study.

METHODS

Ultrasonographic examination using color Doppler imaging (CDI) was performed on the ophthalmic arteries of 46 unselected patients (92 eyes) who have had at least one transient ischemic attack (TIA) and on 32 healthy subjects (64 eyes). The authors recorded the peak systolic and end diastolic velocities and determined the resistivity indices. Iris transillumination photographs were evaluated by two ophthalmologists in a blind trial to show the presence of abnormal iris transluminance of these eyes. Biomicroscopic examination was performed to show the presence of PXS.

RESULTS

The frequency of abnormal iris transluminance in the whole group of patients who had had a TIA and in control subjects was 63% and 28%, respectively (P < 0.05). Pseudoexfoliation syndrome was found in 41% of the right eyes and in 43% of the left eyes in the group of patients who had had a TIA. The difference between the resistivity indices for the ophthalmic arteries of patients who had had a TIA with positive iris transluminance and healthy subjects without transluminance was statistically significant (P < 0.05, Student's t test). Pseudoexfoliation syndrome was detectable in 55.6% of the right eyes and in 61.5% of the left eyes of patients who had had a TIA with abnormal iris transluminance.

CONCLUSION

The exceptionally high frequency of PXS in the eyes of patients who had had a TIA with positive iris transluminance suggests pathologic changes in the blood supply of PXS eyes. High values of resistivity indices for the ophthalmic arteries of these eyes suggest that disturbances in the ciliary circulation may be the possible cause of these changes.

The amount of lens exfoliation and chamber-angle pigmentation in exfoliation syndrome with or without glaucoma

Correlations of the amount of chamber-angle pigmentation and exfoliation material with IOP and with image analysis of the optic discs are reported in the paired eyes of 63 persons with unilateral exfoliation syndrome, and 35 patients with unilateral capsular glaucoma. The effect on IOP of phenylephrine-induced pigmentary dispersion is examined. Chamber-angle pigmentation was more pronounced in capsular glaucoma than in the nonglaucomatous exfoliation eyes (p < 0.01), although the amount of lens exfoliation was the same. In nonglaucomatous exfoliative eyes IOP correlated significantly with the amount of chamber-angle pigmentation (p < 0.01) and exfoliation material (p < 0.05). The nonglaucomatous exfoliative eyes with grade > or = 2 trabecular pigmentation and those with reduction of IOP on phenylephrine provocation had smaller rim areas and rim/disc area ratios than the fellow eyes (p < 0.05). Rather than the amount of exfoliation, the main risk factor for glaucoma seems to be the degree of chamber-angle pigmentation.

Intraocular pressure and prevalence of glaucoma in elderly people in Finland: a population-based study

The distribution of intraocular pressure (IOP) and the prevalence of glaucoma and their correlates were studied in a population-based study of inhabitants aged 70 years or older of three communities in the county of Oulu, Finland. 500 of the 560 eligible subjects (89%) were examined. IOP was measured using applanation tonometry. The diagnosis of glaucoma (or suspected glaucoma) was based on previous history and/or characteristic optic disc changes assessed first by ophthalmoscopy and later by photographic evaluation. No correlation existed between IOP level and age, but IOP was higher in women than in men. Glaucoma occurred in 12% of the participants (60 of 500 persons). In 42 of the 60 persons (8% of the participants) glaucoma had been diagnosed before this survey: non-exfoliative open-angle glaucoma in 15 persons (3.0%), bilateral or unilateral exfoliative open-angle glaucoma in 19 persons (3.8%), and congestive glaucoma in 8 persons (1.6%). In another 18 persons (4% of the participants) new open-angle glaucoma was detected, one third of these were exfoliative. In addition, 6% of the study population had suspected glaucomatous disc changes. In all new glaucoma cases and in all suspected cases the IOP was lower than 25 mmHg. Ocular hypertension (> or = 25 mmHg) without disc changes was found in 2%.

Exfoliation syndrome and the effect of phenylephrine and pilocarpine on pupil size

The horizontal diameter of the pupil was measured on 20 eyes with exfoliation syndrome and 20 control eyes before and after the instillation of 10% phenylephrine and 4% pilocarpine eye drops. Pupil dilation induced by topical application of the alpha 1 adrenoceptor agonist phenylephrine was significantly smaller in eyes with exfoliation syndrome compared to controls. The cholinergic agonist pilocarpine decreased pupil diameter and this effect was significantly less in cases with exfoliation syndrome. We conclude from these data that the pharmacological response to both adrenergic and cholinergic stimulation is weaker in eyes with exfoliation syndrome compared to controls.

Generalized transluminance of the iris and the frequency of the pseudoexfoliation syndrome in the eyes of transient ischemic attack patients

BACKGROUND

Abnormal generalized iris transluminance has been reported to have connection with the pseudoexfoliation syndrome (PXS). According to angiographic studies, microvascular changes are found to be present on the iris of these patients, which suggests that hypoxia has a role in the development of PXS. On the other hand, carotid transient ischemic attack (TIA) patients have been shown to have some ocular key symptoms due to hypoxia.

METHODS

Iris photographs of 62 unselected TIA patients (124 eyes) and 32 healthy subjects (64 eyes) were evaluated in a blind trial to show the presence of iris transluminance of these eyes. Biomicroscopic examination was performed to show the presence of the PXS.

RESULTS

Abnormal iris transluminance was positive in 42% of the right eyes and in 45% of the left eyes in patients in the study group. The corresponding figures for the control group were 16% in both eyes (P = 0.01, chi-square test). When the study group was divided into subgroups according to stenosis of carotid bifurcation, the figures were highest in those cases where one or both carotid arteries were stenosed over 50%. Pseudoexfoliation syndrome was found in 18% of the right eyes and in 23% of the left eyes of TIA patients. The frequency of PXS in these eyes was approximately two times higher than reported in earlier studies of the frequency of PXS in healthy subjects of the same age in a Finnish population.

CONCLUSION

Abnormal iris transluminance is one of the ocular key symptoms of extracranial cerebrovascular disease. Coexistence of cerebrovascular disease with abnormal iris transluminance, together with increased prevalence of pseudoexfoliation supports the theory that hypoperfusion is a contributory factor in the development of PXS.

Exfoliation syndrome in patients scheduled for cataract surgery

A series of 305 consecutive patients 30 years of age or older scheduled for cataract surgery was examined to find out the frequency of exfoliation syndrome, the predominant type of cataract, and the intraocular pressure status. The mean age of 222 (72.8%) females and 83 (27.2%) males was 71.7 (+/- 11.1) years (range 32 to 91 years). Exfoliation was detected in 77 (25.2%) patients. It was unilateral in 37 (48.0%) patients, the affected eye being in 29 (78.4%) cases scheduled for cataract surgery, and bilateral in 40 (52.0%) patients. Exfoliation was increased steadily with age. It was most often seen on the anterior lens capsule (88.9%). Krukenberg's spindle was seen in 31 (20.4%) eyes of patients with and in 12 (2.6%) eyes of patients without exfoliation (p less than 0.001). Nuclear sclerosis predominated in eyes with (83.8%) as compared to those without (61.9%) exfoliation (p less than 0.01). Posterior subcapsular cataract was less common in eyes with exfoliation (1.5%) than in eyes (21.1%) without it (p less than 0.001). A tendency to slightly higher preoperative intraocular pressure was measured in eyes with exfoliation as compared to those without it, and glaucoma occurred much more frequently (33.8% vs 10.8%) in the former group (p less than 0.001). Exfoliation and capsular glaucoma, which must be promptly detected to avoid surgical complications, are frequent in patients scheduled for cataract surgery.

Quantitative assessment of aqueous flare and aqueous 'cells' in pseudoexfoliation syndrome

We used the laser flare-cell meter to measure aqueous flare and aqueous 'cells' in 38 eyes of 38 patients with pseudoexfoliation, in 36 normal control eyes of 36 subjects, and in 19 eyes of 19 patients with chronic open-angle glaucoma unrelated to pseudoexfoliation. In pseudoexfoliation eyes, both aqueous flare (0.61 +/- 0.55 mg/ml human albumin equivalent) and aqueous 'cells' (mean 10.70, range 0-50.6 cells/0.075 mm3) were significantly higher than in the normal control group (flare 0.15 +/- 0.06 mg/ml, 'cells' 0.43, range 0-2, P less than 0.0001) and in the glaucoma group without pseudoexfoliation (flare 0.19 +/- 0.08 mg/ml, 'cells' 0.80, range 0-2.4, P less than 0.0001 and P less than 0.005). No significant difference could be found between the flare and cell counts of normal eyes and glaucoma eyes without pseudoexfoliation (P greater than 0.09, P greater than 0.05) and between PSX eyes with (18 eyes) and without (20 eyes) open-angle glaucoma (P greater than 0.99, P greater than 0.4). Our findings indicate that the blood-aqueous barrier is impaired in eyes with pseudoexfoliation, and that the laser flare-cell meter may be a useful tool to quantify these changes. These alterations of the blood-aqueous barrier need to be considered in medical therapy and intraocular surgery.

Pigmentation of the anterior chamber angle in normal and pseudoexfoliative eyes

Anterior chamber angle pigmentation was gonioscopically graded in 833 persons recruited for the KEYS (Kuopio Eye Survey) during 1989. Pseudoexfoliation was observed in 8.5% in either eye from those born in 1924, the figure being 13.2% for those born in 1914. Anterior chamber angle pigmentation was found to be significantly heavier in eyes with pseudoexfoliation.

Pseudoexfoliation glaucoma in Greece

Pseudoexfoliation glaucoma is commonly seen in Greece, however there is little data concerning the prevalence and characteristics of this disorder. Patients undergoing trabeculectomy for open angle glaucoma were investigated both by the appraisal of the case notes and by re-examination. The prevalence of pseudoexfoliation glaucoma in this population was found to be 87.8%. The characteristics of this disease process in the population studied are discussed. These findings indicate that pseudoexfoliation is a major contributor to severe glaucoma in the population of Northern Greece.

Clinical signs of the pseudoexfoliation syndrome

Pseudoexfoliation syndrome (PXS) is a common cause of glaucoma throughout the world. It is most commonly diagnosed after the observation of pseudoexfoliation material (PXM) on the anterior lens surface. However, there are numerous clinical signs of PXS that should alert the examiner to search carefully for PXM on the anterior lens surface. These include pupillary ruff defects, iris sphincter transillumination, a characteristic whorl-like pattern of particulate pigment deposition on the iris sphincter, particulate pigment deposition on the peripheral iris and trabecular meshwork, and exfoliation material on the zonules and ciliary body. Accuracy of diagnosis is important for purposes of treatment, prognosis, and basic research in he mechanisms of glaucoma, particularly tissue culture.

Cataract and pseudoexfoliation. A clinicopathological study

100 lenses from 98 consecutive patients with senile cataract were investigated histologically for pseudoexfoliation. The patients came from an area known for its high incidence of pseudoexfoliation. The examiner was not aware of the clinical examination at the time of histopathological study. Pseudoexfoliation was observed in 33 lenses. There seemed to be an increasing incidence of pseudoexfoliation with increasing age of the patients. Only 16 of the cases of pseudoexfoliation had been recorded preoperatively, but routine pupillary dilatation had not been carried out. The use of alpha-chymotrypsin at cataract extraction did not preclude histological diagnosis of pseudoexfoliation.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. III. The significane of pigment for the result of the cyclopentolate provocative test in suspected or untreated open-angle glaucoma

Significant elevations of IOP, i. e. responses, occurred in eyes with suspected or untreated open-angle glaucoma during the mydriasis test with 1% cyclopentolate (CPT). The possible role of pigment in the IOP elevations seen in the responders was studied. Pigment was liberated in the aqueous, sometimes very profusely, in 88 (31.9%) of 276 eyes during CPT. The maximal IOP elevations, ad 20 mmHg, were seen in just these eyes. They were eyes with capsular or pigmentary glaucoma or eyes in which exceptionally heavy pigment was demonstrated in the chamber angle for other reasons. There was a statistically significant correlation between pigment liberation and IOP elevation during CPT. Evidently profuse pigment liberation may have caused transient blocking of the trabecular meshwork, obstruction of aqueous outflow and elevation of IOP. Liberation of pigment in the aqueous during CPT was statistically highly significantly more profuse in eyes with pseudoexfoliation than in eyes without pseudoexfoliation. An equally significant correlation with demonstrated between the grade of chamber angle pigmentation and the degree of pigment liberation during CPT. The significance of pigment for IOP elevation was seen also in the statistically highly significantly more profuse pigmentation of the chamber angle in the responder than in the non-responder eyes.

The cyclopentolate provocative test in suspected or untreated open-angle glaucoma. II. Clinical studies on the mechanism of intraocular pressure elevations

The mydriasis provocative test with 1% cyclopentolate (CPT) was performed on 218 patients with suspected or untreated open-angle glaucoma, on 431 eyes in all. Significant IOP elevations (larger than or equal to 8 mmHg) were demonstrated in 21 eyes of 18 patients. The present paper analyses the responder group and presents some other investigation results and clinical findings to throw additional light on the mechanism of IOP elevation in responders. The responders did not differ from the other patients of the material in age or sex. Patients with capsular glaucoma constituted the biggest group among the responders. 48% of the significant IOP elevations during CPT were encountered in eyes with pseudoexfoliation (PE) and open-angle glaucoma. A positive response during CPT was statistically significantly more common in PE eyes than in eyes without PE. Capsular glaucoma was diagnosed immediately or later in all PE eyes which displayed a larger than or equal to 5 mmHg IOP elevation during the CPT. In addition to the importance of pigment in PE eyes, PE material may play a certain role in the elevation of IOP . The mechanism of this role is not known. No correlation was established between the results of the water drinking test and the CPT. The mechanism that causes the elevation of IOP must be quite different in these two tests. Nor was a statistically significant difference observed in the incidence of cataract, the maximal variation of IOP in the 48-h tension curve, the occurrence of cupping of the optic disc or visual field defects between the responder and non-responder eyes in the glaucomatous group.

The exfoliation syndrome: source of the fibrillar material on the capsule

A clinical case of unilateral capsular exfoliation syndrome was observed in the previously traumatized eye of a 22-year-old man with a drawn-down pupil. The distribution of material correspond to the folds of the inner surface of contiguous iris. The periphery of the lens appeared free of deposits. These findings contradict previous theories on the source of the fibrillar material from the lens epithelium and indicate that it is derived from the iris pigment epithelium and not from within the lens capsule, although there is no question but that the lens is involved in a similar process, the products of which probably do not reach the lens surface. The unilateral occurrence of the exfoliation syndrome in a traumatized eye of a 22-year-old man is unique and cannot be explained at this time.